How Etching Concrete With a Gel Acid Increases Performance of Garage Floor Epoxies

The leading cause of garage floor epoxy failure is due to improper surface preparation. By etching concrete with a gel acid risk of coating failure is minimized.

What is Coating Failure

Concrete has unique characteristics that are very different from other building materials. As a result you can not just paint the floor and expect long term performance.

Concrete is porous and subject to moisture pressure that pushes upwards through your concrete slab. Just because you don't see water on your floor doesn't mean it's not there. If your garage floor is on grade the chances of moisture vapor pushing up through the tiny airholes in your slab is high. You may have even noticed a white dust on your floor. This is the result of moisture vapor pushing salts up through your concrete. If your coating has not properly adhered to the surface your will start to see chips and delamination. Gradually your coating will deteriorate and fail.

The Importance of Etching Your Concrete

The most important step before application of a garage floor epoxy coating is to profile the surface increasing the surface area to adhere to. A properly profiled surface will have the feeling of 100 grit sandpaper and any bond breakers will be removed. Bond breakers are salts, oil, dirt, grease or rust.

Professional industrial epoxy applicators profile a floor with a shotblaster. This is a walk behind tool that shoots thousands of tiny ball bearing at the surface. Muriatic and hydrochloric acid will provide a similar result. Most Do It Yourself floor coating manufacturers recommend a liquid acid solution to profile the surface. This method has been used for years with minimal success.

Why Liquid Acid Etching Doesn't Work

Acid does work for etching concrete but the method of application doesn't. Liquid acid is dangerous in pure form so manufacturers dilute the liquid for safety. Then they suggest diluting even more with water. By the time this diluted solution is applied there is very little left to etch your floor.

There are other issues. When you fill your bucket with acid and water it is heavy. The natural tendency is to pour a lot on the floor at first to lighten the load. That means inconsistent application. The next step is to use a broom to agitate the surface.

Using a broom will push some of the small acid particles into the pores of the concrete. When the floor dries and a coating is applied the tiny acid particles stuck in the concrete air holes are reactivated. This breaks down the chemical cross linking of your coating. The result is tiny chips peeling off your floor.

The other issue is that concrete is never flat and the water acid solution will flow to the low spots of the floor. That means whatever etching may be happening is minimal on the high spots. At best the profile is inconsistent. You will notice when coatings fail that it begins on the high spots of your floor.

Gel Technology Has Created an Effective Concrete Etching Solution

Acid is highly effective for profiling concrete, it's the method of application that fails. In recent years Gel Technology has advanced enabling acid to be mixed into a gel. The result is a gel acid that has the consistency of a thick shampoo. It comes in defined amounts of acid. For example you can purchase a 20% or 24% solution that does not require dilution.

Application is by rolling on concrete with a 3/8" nap roller which follows the contour of the surface. Edges and tight areas can be etched by applying with a paint brush. The acid effectively etches the surface while simultaneously pulling bond breakers out of the concrete and is contained in the gel. This is significant. Liquid acid will pull bond breakers out of the surface but they settle right back in the pores. A liquid solution only does a partial job.

Consistent Profiling Provides Increased Coating Adhesion

Etching Concrete with a gel acid has been a breakthrough for long term garage floor coating performance. It was the missing ingredient for years. The results have opened up the garage floor market enabling a small contractor or homeowner to achieve the results of a professional applicator. Profiling concrete with a gel increases surface area enabling your coating to stick for the long term and reducing the chances of coating failure.

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